JPH0133741B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a central air conditioning system.

A centralized air conditioning system distributes hot and cold water generated at one location to a plurality of radiators to control the temperature of a space in which each radiator is provided to a desired temperature.

[Prior art and problems to be solved]

A conventional system of this type is shown in FIG. 9.

In the figure, 1 is a cold/hot water generator that uses gas as a thermal energy source, for example, and this is a cooling water pump 2.
and the cooling tower 3 to generate cold water, and when the cooling water pump 2 and the cooling tower 3 stop functioning, hot water is generated. The cold and hot water generated by the cold and hot water generator 1 is conveyed by the cold and hot water pump 4 to radiators 5 ₁ to 5 _o provided in the space to be air-conditioned. The air conditioned space is equipped with room temperature controllers 6 ₁ to 6 _o .
The action of this regulator opens and closes the two-way valves 7 ₁ to 7 _o connected to the radiators 5 ₁ to 5 _o , thereby maintaining the room temperature within a certain range.

The discharge port of the cold/hot water pump 4 and the cold/hot water generator 1
A pressure detector 8 is provided between the cold and hot water return ports of the two-way valves 7 ₁ to 7 .
7 _o is detected, and based on the detection result, the pressure regulator 9 adjusts the proportional control valve 10.
Opening/closing control is used to bypass cold and hot water.

Note that 11 is a regulator that detects the temperature of the cold and hot water returned to the cold and hot water generator 1 and adjusts the cold and hot water generation capacity.

FIG. 10 shows another conventional example, in which heat sinks 5 ₁ to 5 _o
A three-way valve 7 controlled by a room temperature controller 6 ₁ to 6 _o
1 ' to 7 _o ' are provided, respectively. The three-way valve 7
₁ ' to _7o ' are set so that the pressure loss in the bypass direction is approximately the same value as the pressure loss of the radiators ₅₁ to _5o , and the flow rate and pressure loss characteristics of the cold and hot water system are adjusted to changes in heat load. It is made so that it does not change.

In any of the conventional systems described above, thermal energy such as gas is consumed in an amount corresponding to the thermal load. However, as shown in FIG.
Since it is necessary to maintain a flow rate Q of , the cold/hot water pump 4 consumes a certain amount of power as indicated by a point Y regardless of the magnitude of the heat load.

Generally, air conditioning systems are designed to handle the annual maximum load, but the actual load distribution has the highest point at around 40 to 60% of the maximum load, and the normal cold and hot water conveyance capacity is 60 to 40%. % surplus, and this amount of energy is wasted.

Therefore, the present invention solves the above-mentioned problems, and the cold/hot water pump operates with a cold/hot water conveyance capacity that corresponds to load fluctuations, and the power consumption of the pump becomes optimal according to the load, thereby eliminating unnecessary power consumption. The aim is to provide an air conditioning system that never fails.

[Means for solving problems]

In order to achieve the above object, the air conditioning system according to the present invention comprises a plurality of cold and hot water pumps 4 ₁ to 4 ₄ connected in parallel, as shown in the basic configuration diagram of FIG.
, a differential pressure detector 13 that detects the differential pressure between the suction port and the discharge port of the cold and hot water pumps 4 ₁ to 4 ₄ , a temperature detector 11 that detects the return water temperature of the cold and hot water system, and the temperature A first determining means 9 for determining whether the cold/hot water temperature detected by the detector 11 is within a predetermined temperature range.
a', a second determining means 9b' that determines whether the temperature gradient determined by the change in temperature detected by the temperature detector 11 within a predetermined time is greater than or equal to a predetermined value, and the differential pressure detected by the differential pressure detector 13. A third determining means 9c' for determining whether the absolute _value of the differential pressure obtained is equal to or greater than a predetermined value _; It is characterized by comprising a control means 9d' for increasing or decreasing the number of operating vehicles.

[Effect]

A differential pressure detector 13 detects the differential pressure between the suction port and the discharge port of a plurality of cold/hot water pumps 4 ₁ to 4 ₄ connected in parallel, and a temperature detector 11 detects the return water temperature of the cold/hot water system. , when the detected cold/hot water temperature is within a predetermined temperature range, the temperature gradient obtained from the temperature change within a predetermined time is greater than or equal to a predetermined value, and the absolute value of the detected differential pressure is greater than or equal to a predetermined value. The number of cold and hot water pumps in operation is being increased or decreased.

Therefore, the cold/hot water pump is operated with a cold/hot water conveyance capacity that corresponds to load fluctuations, the power consumption of the pump becomes optimal according to the load, and power is not wasted.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 2 shows an embodiment of the system according to the present invention, in which parts equivalent to those in FIGS. 9 and 10 are given the same reference numerals.

As the cold/hot water pump, five pumps 40 to ₄₄ , which is one more than the number of radiators _{51 to} 54, are connected in parallel, and the discharge side of these pumps _{40 to 44 is} connected in reverse. The stop valves 12 ₀ to 12 ₄ are connected in series, and a differential pressure detector 13 is connected in parallel to the series circuit of each pump and check valve.

4 of the above 5 pumps 4 ₀ to _{4 4} 4 ₁ to _{4 4}
correspond to the radiators ₅₁ to ₅₄ , respectively, and the detection signal from the temperature detector 11 that detects the temperature of the cold and hot water returning to the cold and hot water generator 1, and the signal between the inlet and discharge ports of the pump. The start and stop of the operation is controlled by the controller 9' based on the detection signal from the differential pressure detector 13 that detects the differential pressure.

The pump ₄₀ is always in operation even when there is no demand for heat, so that it can respond immediately when a demand for heat occurs. However, this pump is stopped along with other pumps when heating and cooling operation is stopped.

In addition, two-way valves 7 ₁ to 7 ₄ that are opened and closed by room temperature control devices 6 ₁ to 6 ₄ , respectively, are used as valves for controlling the flow of cold and hot water to the radiators 5 ₁ to _{5 4} . A two-way valve 70 is connected in parallel with each series circuit of the containers ₅₁ to ₅₄ and the two- _way valves ₇₁ to ₇₄ . The two-way valve ₇₀ corresponds to the two-way valve 70, which corresponds to each of the room temperature controllers ₆₁ to ₆₄ .
It is controlled by the output of the NOR circuit 14 so that it opens when the direction valves 7 ₁ to 7 ₄ are closed at the same time. This is because the pump ₄₀ is operating even when there is no demand for heat and there is no need to supply cold and hot water to the radiator, so that amount of cold and hot water is bypassed through the two-way valve ₇₀ .

The differential pressure detector 13 detects the differential pressure between both ends of the series circuit of the pump and the check valve, and supplies this to the controller 9'. Controller 9' is differential pressure detector 1
In response to the differential pressure detection signal from 3, as shown in Figure 3, an on signal is generated to increase the number of pumps by one when the differential pressure is less than P ₁ , and an on signal is generated to decrease the number of pumps by one when the differential pressure is greater than P ₂ . Output each. And the differential pressure
Eliminate the on signal for pump increase or decrease in response to a differential pressure that is △P greater than P ₁ or △P less than P ₂ .

On the other hand, a cold/hot water temperature detection signal from a temperature detector 11 that detects the return water temperature of the cold/hot water system is supplied to the controller 9'. The controller 9' determines whether the temperature is within the range of 10°C to 15°C as shown in FIG. As shown in FIG. 4b, it is determined whether the temperature is within the range of 55°C to 60°C. When it is within the above range, the number of pumps in operation is increased or decreased, and when it is outside the range, the number of pumps in operation is set to the minimum or maximum number as shown in FIG. 4c.

When the temperature is within the above range and the number of pumps in operation is to be controlled, the controller 9' determines the temperature gradient from the temperature change within a predetermined period of time, and determines whether the gradient is greater than or equal to a preset gradient. As a result, as shown in FIG. 5, an ON signal is output to increase or decrease the number of pumps by one, and when the slope is below a predetermined value, an ON signal to increase or decrease the number of pumps in operation is eliminated.

More specifically, in the case of cooling operation, for example, it is determined whether the cold/hot water is within the range of 10°C to 15°C as shown in Figure 4a, and the temperature gradient within a predetermined time is determined as shown in Figure 5. As shown in , it is determined whether the gradient is greater than or equal to a preset slope. The judgment result is, for example, the temperature of cold and hot water is 10.
If the temperature is within the range of ℃ to 15℃ and the temperature gradient is negative and greater than the set value, it can be determined that the heat load on cold and hot water generator 1 has decreased, so the number of operating cold and hot water pumps can be reduced. Control is performed to reduce the amount. If the determination result is that the temperature of the cold/hot water is within the range of 10°C to 15°C, and the temperature gradient is positive and greater than the set value, it is determined that the heat load on the cold/hot water generator 1 has increased. Control is performed to increase the number of operating cold/hot water pumps.

Next, the operation of the above configuration will be explained.

By the operation of two-way valves 7 ₁ to 7 ₄ controlled by room temperature controllers _{6 1} to 6 ₄ , the cold and hot water system is switched to the sixth
Exhibits the characteristics shown in the figure. In other words, if all the radiators ₅₁ to ₅₄ are requesting heat for air conditioning and the flow rate of hot and cold water is _Q3 , the cold and hot water system will have a pressure drop curve _R3 and a head curve _L3. This is true at intersection C. At this time, cold and hot water pumps 4 ₁ to 4 ₄
If the differential pressure between the inlet and outlet of is P ₀ , then P ₀ =
γH becomes ₀ . Here, H ₀ represents the head, and γ represents the specific gravity of cold and hot water, respectively.

Under the conditions described above, some of the radiators stop requesting heat, and the corresponding two-way valve closes.
Assume that the pressure loss characteristics change as shown by curve R ₂ as shown in FIG. At this time, the difference P ₂ (>P ₀ ) between the pump suction port and the pump discharge port becomes P ₂ =γH ₂ . This differential pressure is detected by the differential pressure detector 13, and a differential pressure detection signal corresponding to the differential pressure is sent to the controller 9'.
Based on this differential pressure detection signal, the controller 9' can supply a stop signal to some of the pumps ₄₁ to ₄₄ in order to reduce the number of operating cold/hot water pumps as shown in FIG. become a state.

At this time, the temperature detector 11 detects the temperature of the return water of the cold/hot water system and sends a detection signal to the controller 9'. The controller 9' performs the following processing on the temperature detection signal.

In the case of cooling operation, it is determined whether the detected temperature is within the range of 10°C to 15°C. If the temperature is within the above range, the gradient of the temperature over a predetermined time period is calculated, and it is determined whether the temperature gradient is greater than or equal to a preset value. If the determination result is YES and the temperature gradient is negative, it is determined that the heat load has decreased and the number of operating cold/hot water pumps is reduced by supplying the above stop signal to one pump and causing that pump to operate. stop. By stopping the operation of this pump, the cold/hot water system is established at the intersection B of curves R ₂ and L ₂ in FIG. 6.

Furthermore, if the heat load decreases and the differential pressure increases, and the cold/hot water temperature is within the cooling temperature range and the temperature gradient is negative, the number of pumps in operation decreases and a new curve is created.
A cold/hot water system is established at the intersection A of R ₁ and L ₁ .

Furthermore, when the heat load increases, the cold/hot water system moves to the intersection of the curve L ₁ and the curve R ₁ in FIG. 6, and a differential pressure P ₁ =γH ₁ occurs. In response to the differential pressure signal generated by the differential pressure detector 13, the controller 9' becomes ready to supply an increase signal to the pumps to increase the number of pumps in operation.

In this state, if the temperature of the hot and cold water is within the cooling temperature range and the temperature gradient is positive, the controller 9' supplies the operation signal to the pumps in order to increase the number of pumps in operation by one. As a result, the cold/hot water system is operated at the intersection B of curves R ₂ and L ₂ .

When the heat load further increases, the differential pressure detector 1
3 sends a differential pressure detection signal to the controller 9' to increase the pump, so the controller 9' enters a standby state to increase the pump. Then, when the temperature condition and temperature gradient condition are satisfied, the actual number of pumps in operation is increased.

FIG. 7 is a flowchart summarizing the work performed by the controller 9' during cooling and heating.

In the above embodiment, the controller 9' is constituted by a microprocessing unit (CPU) that processes the differential pressure detection signal and the temperature detection signal according to a predetermined program to start and stop the pump. However, this can be changed as shown in FIG.

In FIG. 8, the differential pressure detector 13 detects the differential pressure P ₁
Normally open switch S ₁ and differential pressure that are turned on by detection of:
The controller ₉ ' consists of an up-down counter _9a , which constitutes a pump sequential increase/decrease section, and a und comparator and gradient detection section, which constitute a temperature range and gradient determination section. It consists of a circuit 9b and switches S ₃ and S ₄ controlled by the detection circuit 9b.

The above window comparator and slope detection circuit 9
Based on the temperature detection signal from the temperature detector 11, b uses a comparator to determine whether or not the cold/hot water temperature is within the cooling/heating range, and also determines the gradient based on the temperature change within a predetermined time, and
A control signal is sent to l ₁ and l ₂ to cause the counter 9a to count up or down, or to set its contents to the minimum or maximum value.

Therefore, when the switches S ₁ and S ₂ are turned on, the counter 9a counts up to increase the number of pumps in operation, and when the switches S ₂ and S ₄ are turned on, the counter 9a increases.
will count down and reduce the number of pumps in operation,
In response to the fact that the cold/hot water temperature is not within the predetermined temperature range, the counter 9a is set to the minimum or maximum value to minimize or maximize the number of pumps in operation.

In addition, as a cold/hot water pump, pole number switching and Y-△
If switchable pumps are operated in parallel, the pump capacity can be controlled more precisely according to the load.

〔Effect of the invention〕

As explained above, according to the present invention, the cold/hot water pump is configured by connecting a plurality of pumps in parallel, and the number of operating pumps is increased or decreased according to load changes. Electricity is adjusted according to the load, resulting in savings in electricity costs compared to conventional systems that constantly operate the pump at maximum capacity.
Economical.

In particular, differential pressure control using a single speed control method is used to control the number of pumps, which is inexpensive in equipment cost and easy to maintain. Control without hunting is now possible.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the basic configuration of the air conditioning system according to the present invention, Fig. 2 is a block diagram showing an embodiment of the system according to the present invention, and Fig. 3 shows the operation of the controller based on the differential pressure detection signal. An explanatory diagram to explain,
Figures 4 and 5 are explanatory diagrams explaining the operation of the controller based on the temperature detection signal, Figure 6 is a graph showing the characteristics of the hot and cold water system of the system in Figure 2, and Figure 7 is the system in Figure 2. A flowchart showing the work performed by the internal controller, Fig. 8 is a block diagram showing a modification of a part of Fig. 2, Fig. 9 is a block diagram showing a conventional system, and Fig. 10 is another conventional system. FIG. 11 is a graph showing the characteristics of the cold/hot water system of the systems shown in FIGS. 9 and 10. 4 ₁ to 4 ₄ ...cold/hot water pump, 9'...controller, 9
a'...first judgment means, 9b'...second judgment means, 9
c'...Third determination means, 9d'...Control means, 11...Temperature detector, 13...Differential pressure detector.

Claims (1)

[Claims] 1. A plurality of parallel-connected cold and hot water pumps, a differential pressure detector that detects the differential pressure between the inlet and discharge ports of the cold and hot water pumps, and a temperature detector that detects the return water temperature of the cold and hot water system; A first step that determines whether the cold and hot water temperature detected by the temperature detector is within a predetermined temperature range.
a second determining means for determining whether a temperature gradient determined by a change in temperature detected by the temperature detector within a predetermined time is greater than or equal to a predetermined value; and a differential pressure detected by the differential pressure detector. An air conditioner characterized by comprising: third determining means for determining whether the absolute value of is greater than or equal to a predetermined value; and a controlling means for increasing or decreasing the number of operating cold/hot water pumps according to the logical product output of each determining means. system.